1. Field of the Invention
The present invention relates to an electric heater, and more particularly, to an electric heater in which a halogen lamp is mounted in a reflecting plate, and a subsidiary reflecting plate is provided at the front of the halogen lamp, whereby efficiency of heat reflection can be enhanced and durability can be increased.
2. Description of the Prior Art
With the improvement in living standard, electric heaters have widely been used as an indoor heating apparatus instead of the previous oil heaters. In accordance with the increasing demand for the electric heater, various types of electric heaters have been developed.
As is well known, the basic principle of electric heater is to heat the surrounding air with the heat generated by supplying electric current for the heating wires which are protected by a safety cage disposed with a certain space. In addition, the electric heater is provided by appurtenants for effectively irradiating the heat generated from the heating wires. As a typical example thereof, an electric heater in which a reflecting plate prepared by bending a rectangular shaped thin metal sheet is disposed in a rear portion of heating wires has been pervaded, but a satisfactory effectiveness could not be obtained. In the electric heater as described above, there was a problem that heat cannot be transferred to the desired point in the distance. In fact, if electric current of the heater is increased in order to deliver sufficient heat, dangers of overheat and fire may be accompanied. On the contrary, if the current is decreased in order to avoid any possible accidents, it is difficult to obtain a satisfactory heating effect.
In order to solve the problem involved in the above conventional heater, Korean Utility Model Laid-Open Publication No. 98-61527 discloses an improved radiant type heater which can transfer an appropriate amount of heat to the desired point in the distance so that the indoor air can sufficiently be warmed. In such a radiant type heater, a spherical reflecting plate is installed at the rear portion of heating wires, and the diameter of a wire mounting portion is gradually decreased toward the rear portion so that heat is not scattered into all directions but concentrated in narrow range, whereby heat can be transferred to the desired point in the distance.
Specifically, referring to FIGS. 1 and 2, the prior art electric heater 1 is divided into a heating part 10 including a heating wire 12 and a supporting part 20. At first, in the supporting part 20, a main circuit for operating and controlling radiant type heater is installed in a supporting anvil 21. Also, a power switch 22 for supplying or breaking electric power, a temperature controlling switch 23 for controlling electric power on the basis of a specific temperature in order to maintain temperature of the heating wire in appropriate range, a power display lamp 24 for displaying as to whether electric power is supplied or not, a safety switch 29 for controlling electric power according to the tilt of the electric heater and an alarm lamp 25 for showing a signal to user when the electric heater is tilted extremely, etc., are disposed in the lower and the upper portions of the supporting anvil 21.
In addition, the heating part 10 and the supporting anvil 21 are connected with each other via a first supporting post 26 and a second supporting post 27. If a control knob 28 is released, the second supporting post 27 can be put into or extracted from the first supporting post 26. That is, overall height of the heater can be adjusted.
With reference to FIG. 2 showing the enlarged heating part of the radiant type heater according to the prior art, the heating part 10 comprises a heating wire 12 which is wound round a wire mounting portion 11 having a certain shape, a reflecting plate 13 which is disposed in the rear portion of the heating wires, a safety cage 14 which is connected to the reflecting plate and forms a compartment of the front part of the overall heating part 10, and a supporting case 15 which is connected to the rear part of the reflecting plate 13. On the other hand, the heating wire 12 is connected to the reflecting plate 13 by means of a bracket 16, and a plurality of heating sensing rods 17 are fixed to the front end of the reflecting plate. Therefore, the heat rays a emitted from the heating wire 12 is concentrated into a certain range C by the reflecting plate 13, unlike the structure in which heat is scattered into all directions. Consequently, the heat can be reached to the desired position in the distance. The heat rays a are not stagnated around the heating portion 10 including the heating wire but radiated through the reflection process via the reflecting plate to prevent overheat of the safety cage 14. Here, the maximum heat ray convergence effect can be achieved in a case where the reflecting plate 13 has a concave shape; that is, the central portion of the reflecting plate is concave including a spherical surface such as a conventional concave mirror.
Meanwhile, the wire mounting portion 11 around which the heating wire 12 is wound is prepared from a heat-resistant material such as ceramics and has a circular cone shape, and the diameter of the wire mounting portion 11 is gradually decreased toward the rear portion so that all heat rays a generated from the heating wire 12 are directed to the reflecting plate 13 to prevent some of the heat rays from scattering out of a certain range C. An object of the invention can be achieved although the shape of the wire mounting portion 11 is neither a circular corn, a triangle nor polygonal horn. In other words, it is possible to use all shapes of the wire mounting portion 11 having a diameter which is gradually decreased toward the rear end.
It is true that the electric heater with the structure as described above has a superior heat efficiency. However, since the heating wire is formed in a coil shape, the heating coil of the heater is corroded if the heater is used for a long time which provokes problems that durability is low and there is a danger of fire.
Therefore, an object of the present invention is to provide an electric heater which can overcome the prior art problems, and which utilizes a halogen lamp and a subsidiary reflecting plate which is disposed at the front portion of a halogen lamp so that reflection efficiency and durability can be improved.
To achieve this object, the heater according to the present invention was constructed so that a halogen lamp is used as a heating means, and a reflecting plate is disposed in the front portion of the halogen lamp and is fixed to a safety cage.